344 HISTORY OF PERSIA CHAP. He wrote letters, moreover, to the Governors of the various provinces, denouncing the treaty and threatening with expulsion from the sect and with death all Shias who refused to fight. At the same time he took the more formal step of despatching an envoy to Constantinople with the laconic message, cc Restore the provinces of Persia or prepare for war." Having by these means excited the inhabitants of the country against their Shah, Nadir Kuli marched to Isfahan. There he upbraided Tahmasp, and then seized him and sent him prisoner to Khorasan ; but, as lie did not yet feel in a position to usurp the throne, he had recourse to the ancient device of an infant puppet in the person of a son of Tahmasp, and was himself proclaimed Regent. The Battle of Karkuk, A.H. 1146 (1733).—Nadir's second campaign opened with the siege of Baghdad, whose defender, Ahmad Pasha, after being defeated in the open, was prepared to offer a desperate resistance. The situation, however, was entirely changed by the advance of a power- ful Turkish army under Topal1 Osman. Nadir unwisely divided his force and, leaving twelve thousand men to occupy the trenches before Baghdad, marched north to meet the Turks at Karkuk or Kirkuk, near Samarra. The battle was one of the fiercest ever fought between the two nations. At first the Persians gained an advantage in defeating the Turkish cavalry, but the flight of the horsemen left the formidable Ottoman infantry unmoved, and its advance restored the battle. Nadir had expected aid from a body of Arabs, but they attacked one of his flanks. Gradually the battle went against the Persians, the horse of the. Persian leader was twice shot under him, and his standard-bearer fled, believing him to be killed. This decided the day, and after eight hours' desperate fighting, the Persian army was routed. The news quickly reached Baghdad, where the isolated Persian division was then annihilated. The main army fled in disorder and in a state of such demoralization that it was not re-formed 1 Topal signifies a " cripple.'* As a young man Osman had been badly wounded and be never recovered the full use of his legs.